Well, of course there's Enders Game
But I assume you've already read it.
Neal Stephenson is a good writer, sci-fi as well as (semi-alternate) history (the Baroque Cycle trilogy) but you've gotta stomach roughly three hundred pages per book, in small print. And you've got multiple simultaneous storylines intertwining with each other, and sometimes stuff may seem chaotic and nonsensical, but in the end
everything falls into place. You've got to like open endings, though.